Slither, the Solidity source analyzer

Slither is a Solidity static analysis framework written in Python 3. It runs a suite of vulnerability detectors, prints visual information about contract details, and provides an API to easily write custom analyses. Slither enables developers to find vulnerabilities, enhance their code comphrehension, and quickly prototype custom analyses.

Features

• Detects vulnerable Solidity code with low false positives
• Identifies where the error condition occurs in the source code
• Easily integrates into continuous integration and Truffle builds
• Built-in 'printers' quickly report crucial contract information
• Detector API to write custom analyses in Python
• Ability to analyze contracts written with Solidity >= 0.4
• Intermediate representation (SlithIR) enables simple, high-precision analyses
• Correctly parses 99.9% of all public Solidity code
• Average execution time of less than 1 second per contract

Usage

Run Slither on a Truffle application:

slither .

Run Slither on a single file:

$ slither tests/uninitialized.sol 
[..]
INFO:Detectors:
Uninitialized.destination (tests/uninitialized.sol#5) is never initialized. It is used in:
	- transfer (tests/uninitialized.sol#7-9)
Reference: https://github.com/trailofbits/slither/wiki/Vulnerabilities-Description#uninitialized-state-variables
[..]

Slither can be run on:

• A .sol file
• A Truffle directory
• A directory containing *.sol files (all the *.sol files will be analyzed)
• A glob (be sure to quote the argument when using a glob)

Configuration

• --solc SOLC: Path to solc (default 'solc')
• --solc-args SOLC_ARGS: Add custom solc arguments. SOLC_ARGS can contain multiple arguments
• --disable-solc-warnings: Do not print solc warnings
• --solc-ast: Use the solc AST file as input (solc file.sol --ast-json > file.ast.json)
• --json FILE: Export results as JSON

Detectors

By default, all the detectors are run.

Num	Detector	What it Detects	Impact	Confidence
1	shadowing-state	State variables shadowing	High	High
2	suicidal	Functions allowing anyone to destruct the contract	High	High
3	uninitialized-state	Uninitialized state variables	High	High
4	uninitialized-storage	Uninitialized storage variables	High	High
5	arbitrary-send	Functions that send ether to arbitrary destinations	High	Medium
6	controlled-delegatecall	Controlled delegatecall destination	High	Medium
7	reentrancy-eth	Reentrancy vulnerabilities (theft of ethers)	High	Medium
8	incorrect-equality	Dangerous strict equalities	Medium	High
9	locked-ether	Contracts that lock ether	Medium	High
10	shadowing-abstract	State variables shadowing from abstract contracts	Medium	High
11	constant-function	Constant functions changing the state	Medium	Medium
12	reentrancy-no-eth	Reentrancy vulnerabilities (no theft of ethers)	Medium	Medium
13	tx-origin	Dangerous usage of tx.origin	Medium	Medium
14	uninitialized-local	Uninitialized local variables	Medium	Medium
15	unused-return	Unused return values	Medium	Medium
16	shadowing-builtin	Built-in symbol shadowing	Low	High
17	shadowing-local	Local variables shadowing	Low	High
18	calls-loop	Multiple calls in a loop	Low	Medium
19	reentrancy-benign	Benign reentrancy vulnerabilities	Low	Medium
20	timestamp	Dangerous usage of block.timestamp	Low	Medium
21	assembly	Assembly usage	Informational	High
22	constable-states	State variables that could be declared constant	Informational	High
23	external-function	Public function that could be declared as external	Informational	High
24	low-level-calls	Low level calls	Informational	High
25	naming-convention	Conformance to Solidity naming conventions	Informational	High
26	pragma	If different pragma directives are used	Informational	High
27	solc-version	Incorrect Solidity version (< 0.4.24 or complex pragma)	Informational	High
28	unused-state	Unused state variables	Informational	High

Contact us to get access to additional detectors.

Printers

To run a printer, use --print and a comma-separated list of printers.

Num	Printer	Description
1	call-graph	Export the call-graph of the contracts to a dot file
2	cfg	Export the CFG of each functions
3	contract-summary	Print a summary of the contracts
4	function-summary	Print a summary of the functions
5	human-summary	Print a human readable summary of the contracts
6	inheritance	Print the inheritance relations between contracts
7	inheritance-graph	Export the inheritance graph of each contract to a dot file
8	slithir	Print the slithIR representation of the functions
9	slithir-ssa	Print the slithIR representation of the functions
10	vars-and-auth	Print the state variables written and the authorization of the functions

How to install

Slither requires Python 3.6+ and solc, the Solidity compiler.

Using Pip

$ pip install slither-analyzer

Using Git

$ git clone https://github.com/trailofbits/slither.git && cd slither
$ python setup.py install 

We recommend using an Python virtual environment, as detailed in the Developer Installation Instructions, if you prefer to install Slither via git.

Using Docker

Use the eth-security-toolbox docker image. It includes all of our security tools and every major version of Solidity in a single image. /home/share will be mounted to /share in the container. Use solc-select to switch the Solidity version.

docker pull trailofbits/eth-security-toolbox

To share a directory in the container:

docker run -it -v /home/share:/share trailofbits/eth-security-toolbox

Getting Help

Feel free to stop by our Slack channel (#ethereum) for help using or extending Slither.

• The Printer documentation describes the information Slither is capable of visualizing for each contract.

• The Detector documentation describes how to write a new vulnerability analyses.

• The API documentation describes the methods and objects available for custom analyses.

• The SlithIR documentation describes the SlithIR intermediate representation.

License

Slither is licensed and distributed under the AGPLv3 license. Contact us if you're looking for an exception to the terms.